ZANZIBAR, Tanzania  Zanzibar imposed a ban on plastic shopping bags this week to protect the country's beleaguered environment, an official said Wednesday.

Anyone found producing, importing, using or selling plastic bags after Thursday could face a fine of up to US$2,000 (euro1,600) and a possible jail sentence of up to a year, said Ali Juma, Zanzibar's director of environmental protection.

The ban -- which applies only to thin, transparent polyvinylchloride bags -- was necessary because the bags clogged sewers and produced poisonous fumes when burned, he said.

"We are enforcing the law on hazardous products and waste," Juma said. He did not say what people should do with the bags they already have.

The Indian Ocean archipelago, home to 1 million people, lacks the technology to recycle plastic. It also faces serious marine and land pollution problems.

Until now, Zanzibar has imported 350,000 tons of plastic bags per year. The duty on those bags had brought in more than US$1 million in tax revenue, said Juma Omar of the Zanzibar Chambers of Commerce.